Non-laminated, non-dyeable metallic yarn

ABSTRACT

A non-dyeable coated metallic flat yarn cut from a transparent film metallized on both sides and coated on both sides with an ethylene copolymer, preferably an ethylene acrylic acid copolymer containing 2-15 percent acrylic acid.

United States Patent [191 Schoots NON-LAMINATED, NON-DYEABLE METALLIC YARN [75] Inventor: Peter J. Schoots, Anderson, SC.

[73] Assignee: Lurex N.V., Amsterdam,

Netherlands [22] Filed: June 7, 1972 [21] Appl. N0.: 260,673

[52] US. Cl. 117/68, 117/71 R, 117/76 T, 117/138.8 F [51] Int. Cl. B05c 9/04 [58] Field of Search... 117/68, 71 R, 76 T, 138.8 F,

117/161 UC, 161 UH [56] References Cited UNITED STATES PATENTS 2,974,055 3/1961 Scharf 117/71 X [451 Sept. 24, 1974 3,069,746 12/1962 Scharf 161/220 X 3,244,544 4/1966 Scharf 117/71 X 3,311,486 3/1967 Scharf 117/15 X 3,399,070 8/1968 Scharf 117/68 X 3,520,861 7/1970 Thomson et a1. 117/161 X Primary ExaminerWil1iam D. Martin Assistant Examiner-M. R. Lusignan Attorney, Agent, or Firm-George F. Helfrich [5 7] ABSTRACT 4 Claims, No Drawings NON-LAMINATED, NON-DYEABLE METALLIC YARN BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates generally to textiles. In particular it provides a flat, highly reflective metallized continuous filament textile yarn which is not dyed by any conventional coloring methods.

2. Prior Art Metallic yarns have long been used to provide particular styling effects in apparel and in fabrics used for upholstery, etc. These yarns normally represent only a minor portion of the total fabric and are there solely for decorative and styling effect and serve no other functional purpose. Such yarns were first made by laminating transparent cellophane films over metal foils. As other transparent plastic films became available these replaced regenerated cellulose films.

Such yarns are now made principally from polyethylene-terephthalate films laminated to metal foils or metallized by high vacuum metal vaporization processes followed by lamination or by the application of a protective plastic coating to protect the reflective metal from abrasion, tarnishing, and the chemical action of the wet processes which fabrics are exposed to in the course of their dyeing and finishing, as well as similar effects on finished articles which are subjected to wear and washing or dry cleaning.

Non-laminated metallic yarns like those disclosed by US. Pat. No. 2,974,055 provide lighter weight, more pliable, less stiff yarns which consequently yield more yards to the pound of yarn thus providing the decorative and styling effect more economically, especially for light weight apparel fabrics.

Colored metallic yarns have been provided by pigmenting or dyeing the adhesive for lamination, dyeing the transparent plastic film or coloring the coating material. The dyeing of fabrics containing metallic yarns has been possible only with definite limitations. See, for example US. Pat. No. 3,069,746. Highly reflective metallic yarns having all the properties desirable in textile yarns, which are not colored by some or all of the dyeing or coloring procedures normally applied to fabrics have never been available. All prior art metallic yarns either have been colored by selected dyestuffs or have been stained by the procedures required for the coloration of fabrics containing them. (Obviously metal fibers or yarns could be expected to be non-dyeable, but because of weight, stiffness, tarnishability and economics, metals have found no significant application in modern times.) Such staining results in undesirable muddy" effects, lacking the brightness desired, or in colors which are not fast and may change with exposure to light, or lack crock fastness so that they transfer to other fabrics when rubbed. This property of prior art metallic yarns has limited the procedures useful for coloring fabrics containing them, resulting in compromises with respect to shades and shade range available, or has required additional processing to overcome deficiencies.

SUMMARY OF THE INVENTION This invention provides a metallic yarn which is reserved (i.e., does not dye) in all those dyeing procedures applied to synthetic and natural fibers and fabrics comprising them. These yarns are slit from plastic webs which have been metallized on both sides and coated on both sides with a thin coating of an ethylene copolymer, preferably an ethylene-acrylic acid copolymer.

DESCRIPTION or THE PREFERRED EMBODIMENTS Preparation of the metallized plastic webs used for these coated metallic yarns is by procedures wellknown in the art. Plastic films are plated with metal in high vacuum chambers by thermal evaporation or cathodic sputtering techniques. Both sides are metallized. Aluminum, tin, silver, gold, copper, and/or selected alloys can be used. A thin, adherent, highly reflective metal plating is applied to the films by these procedures, all well-known in the art. The films can be cellophane or thermoplastic materials. Most commonly cellulose acetate or polyethylene-terephthalate films are used. Films as wide as forty inches (40") of selected weight, 25, 50, or gauge (0.25, 0.5, or 1.0 mils thick) are used. The metal plating is then covered by a thin coating of polyethylene copolymer containing at least about 85 percent ethylene with a comonomer selected from the group consisting of acrylic acid, methacrylic acid and the lower alkyl acrylate or methacrylate esters. Copolymers includes terpolymers. The undesirable dyeability of the coating material increases with comonomer content and with the alkyl chain length when alkyl ester comonomers are used, particularly with dispersed dye stuffs. These coatings can be applied as films by calendaring such a film onto each side of the metallized web, but this makes relatively thick, stiff yarns which are undesirable for the applications for which non-laminated coated metallic yarns are normally used. In order to provide the flexible coatings the ethylene copolymer is applied as a dispersion. These dispersions are prepared by dissolving the selected ethylene copolymer in hot chlorinated hydrocarbon and then dispersing the solution in, for example, methyl ethyl ketone containing a small amount of a stabilizing resin latex. vinyl-chloride-vinyl acetate copolymer latexes, nitrile rubber, and/or silicon latex are useful for dispersion stabilizer. The sole purpose of the stabilizer, however, is to provide a dispersion of the ethylene copolymer which will remain dispersed until it is applied by coating roller as a liquid application to the metallized plastic film. Other dispersing agents, wellknown to those skilled in the art, will serve this purpose equally well. The final weight of the ethylene copolymer coating can vary from about 0.2 gram per square meter to about 1.0 gram per square meter. A coating weight of about 0.3 g/square meter is preferred for ethylene copolymers containing 2-15 percent acrylic acid. Good continuous coatings require selected molecular weight ethylene copolymer. Copolymers having melt index below 20 are preferred. It is necessary that the applied dispersion of the ethylene copolymer be dried at temperatures above 80 C. in order that continuous transparent coatings are obtained.

After the metallized films are coated with the ethylene copolymer dispersion and dried, metallized yarns are produced by slitting the film. Such yarns are 1/ inch to H4 inch in width. Typically such a yarn, l/69 inch wide, produced by slitting a metallized and coated 50 gauge polyethyleneterephthalate film has a tensile strength of about 82 grams, elongation of 104 percent,

yield point of 49 grams, and will yield 150,000 meters of yarn per kilogram.

Fabrics containing these metallic yarns may be dyed by all of the usual dyeing procedures recognized by the art. These include acid dyeing, direct dyeing. basic dyeing, and disperse dyeing depending on the class of dye stuff selected, which selection will usually be determined by the yarns comprising the majority of the fabric. Direct dyeing might be selected for a fabric made principally of cotton or viscose rayon with metallic yarn, acid dyeing for W001 or nylon, basic dyeing for acrylics and disperse dyeing for acetate rayon or polyester. Carrier and high temperature dyeing with disperse dyes may be required, particularly for fabrics containing polyester fibers. It is under these latter conditions that the yarn of this invention will show spectacular improvement in its reserving properties over any of the coated or laminated metallic yarns of the prior art. Under these conditions the plastic films from which laminated yarns are made or the coatings employed for coated yarns of the prior art will almost inevitably be colored while the yarn of this invention will remain clean and bright. Outstanding reserving properties of the yarn of this invention will be particularly evident when included in piece goods which are dyed to medium and dark shades. All prior art metallic yarns are deeply colored under these conditions while the yarn of this invention will not be.

The various dyeing procedures serve as tests for the (lCl), 11/2 percent Nylomine Acid Blue C-3RS (1C1) at pH 6 (acetic acid) and dyed for 10 minutes at 92C.

For carrier dyeing of polyester yarns a variety of chemical types of carriers are used. These may include diphenyl. methyl naphthalene. methyl salicylate. orthophenylphenol, butyl benzoate, and trichlorobcnzene. Proper selection of carrier is necessary for carrier dyeing of polyesterfabrics containing the metallic yarn of this invention. Orthophenylphenol (particularly as sodium salt), aromatic ester, and aromatic ether types are useful. This metallic yarn will be satisfactorily reserved in all these systems.

Another test frequently used for the evaluation of metallic yarns is a soap boil test in which the yarn is boiled in an aqueous solution containing about 5 grams of soap per liter (pl-l about 9) for 2 hours. This test evaluates the alkali resistance of the metallic yarn. As might be expected the yarn of this invention has some limitations on exposure to hot alkaline conditions. It is necessary to avoid pH conditions exceeding 7.5-8.0 at elevated temperatures. Nevertheless. the yarn of this invention is completely satisfactory under fabric dyeing and processing conditions and will not be harmed by usual washing practices.

in order to indicate the ability of the yarns of this invention to withstand the above tests observations of chemical attack, peeling of the coating, and loss of metal, are made and the results reported by a numerical rating reflecting resistance of the specimens on the yarn of this invention particularly when it is included in following scale:

Chemical ttac k Coating Peeling Demetallization knitted fabrics with polyes ter and/or nylon yarns. Typical conditions for these procedures follow:

Carrier Dyeing Disperse Dyestuffs the knitted fabric containing polyester yarn and the metallic yarn is introduced into the dyebath at a liquor ratio of 40: 1. The bath contained 3.5 g/l Tumescal OP (lmperial Chemical industries Limited) carrier, adjusted to pH 5.5-6 with acetic acid. Ten percent 10 percent) on the weight of the fabric of Duranol Direct Black T (lCl) was added and the dyeing was carried out for three hours at 100C.

H. T. Dyeing Disperse Dyestuffs The knitted fabric containing polyester yarn and the metallic yarn was dyed under pressure with 4 percent dyestuff [Palanil Rosa BF (Badische Anilin and Soda Fabrik A.G.)l in a liquor ratio of 40:1, adjusted to pH 5.0-5.5 with acetic acid, for 2 hours at 125C.

Carrier Dyeing with Basic Dyestuffs The knitted fabric containing polyester yarns and the metallic yarn was introduced into a bath at 40:1 liquor ratio contain ing 1.5 g/l Carolid ELF/C (Tanatex) carrier, 3g/1 sodium sulfate, 2 percent Synacril Fast Blue R (1C1) at pH 5-6 (acetic acid) and dyed for 80 minutes at 100C.

Acid Dyestuffs The knitted fabric containing nylon yarns and the metallic yarn was introduced into a bath at 40:1 liquor ration, containing 2.5 percent sodium sulfate, /2 percent Nylomine acid Yellow C-3GS A typical result might be reported 1/2/1, for example, showing very slight chemical attack, slight peeling of the coating, and O-3 percent demetallization.

The invention can be better understood by reference to the following specific examples. The examples are given in order to enable those skilled in the art to make and use the invention but are not intended to define the limits of the invention.

EXAMPLE 1 Ethylene, acrylic acid and a solvent were fed continuously at rates respectively of 10.01, 0.01 and 2.70 pounds per hour into and through a two liter stirred autoclave maintained at a temperature of l40l50C. and a pressure of 1,450 atmospheres. Azo-bisisobutyronitrile initiator was also fed continuously at a rate equivalent to about 0.8 pounds per 1,000 pounds of polymer product. The residence time in the autoclave was about 15 minutes. The reaction mixture, continuously removed from the autoclave, was stripped of unpolymerized monomers and solvent under reduced pressure at elevated temperature. After operations had reached a steady state the conversion of monomers to copolymer was 12.4 percent, the copolymer had a melt index of 40 and contained about 92 percent ethylene and 8 percent acrylic acid.

Similarly other polyethylene copolymers can be prepared by proper selection of comonomer. Adjustment of temperature and/or catalyst composition can be used to regulate the melt index of the copolymer obtained.

Melt index is determined by ASTM test method D- 1238-52T (ASTM Standards 1955, Part 6, pages 292-295). With a given composition, melt index is a well recognized determination of molecular weight.

EXAMPLE 2 Fifteen grams of an ethlene-acrylic acid copolymer,

containing 8 percent acrylic acid, with melt index of 5.0 was dissolved in 300 g of boiling perchloroethylene. This hot solution was poured into 200 g of methyl ethyl ketone containing 0.75 g of a poly (vinyl chlorideacetate) latex (VAGH available from Union Carbide) with stirring. The resulting dispersion had a temperature of approximately 70C. The dispersion was cooled to room temperature and placed in the fountain of a rotogravure printing press.

Metallic yarns were produced by coating a 50 gauge clear polyethylene terephthalate film having a highly reflective deposit of aluminum on each side thereof with a layer of this dispersion, passing the film through an oven at 8090C. to evaporate the solvent, and repeating the coating of the other side of the polyethylene terephthalate film. A clear, transparent coating of ethylene acrylic acid polymer approximately 0.3g per square meter was deposited on each side of the metallized polyethylene terephthalate film. The film was then passed over a rotating cutter and slit to yarns l /50 to 1/4 inches in width.

A sample of this metallic yarn 1/69 inches in width has the following properties:

Silver Color Strength 82 g Elongation to break 109% Yield point 49 g Yield 150,000 meters/kg.

The yarn was knitted into fabric and tested by the dyeing tests set forth above. The test results follow:

Standard boil test 7 Poor i "mane 3 5 Metallic yarn samples are prepared in like manner by coating ethylene copolymer compositions set forth in the following Table I along with properties obtained by testing the yarns.

EXAMPLE 4 in order to determine the dyeability of the copoly- 5 mers to be used for coating the metallized film, granules of the various copolymer compositions were exposed to the test for carrier dyeing with Dispersed Dyestuffs, yielding the following results:

because the reflective aluminumn prevents exposure of the colored substrate to light.

The color of metallic yarns of this invention is essentially limited to the color of the metal deposit. While very light shades are possible by the addition of selected pigments to the dispersion of polyethylene copolymer before coating, pigment coatings for even light or medium shades are impractical with these extremely thin coatings.

'' Whatis claimed is:

l. A non-laminated, non-dyeable metallic flat yarn cut from a thermoplastic film having a highly reflective metal deposit on both sides thereof coated with a thin layer of a copolymer comprising at least about 85 percent ethylene with the remainder being a monomer selected from the group consisting of acrylic acid, methacrylic acid, and alkyl esters of acrylic acid or methacrylic acid having 1-3 carbon atoms in the alkyl group.

TA LE 1 Sample No. Copolymer Composition Melt lndex Yarn Test Results Disperse Dye Acid Basic arrier HT D e D c 1 98% ethylene 2% acrylic acid 5 1/1/0 1/1/1 0/0/0 l/l/O 2 95.5% ethylene 4.5% acrylic acid 5. l/l/O l/l/O 0/0/0 1/0/0 3 92% ethylene 8% acrylic acid 5. l/l/O 1/1/0 l/0/0 1/1/0 4 83.2% ethylene 16.8% acrylic acid 6 2/3/0 3/3/3 2/0/0 3/2/0 5 80% ethylene 20% acrylic acid 5. Not printable 6 88.2% ethylene 11.8% methacrylic acid 1/2/1 7 81.2% ethylene 9.8% acrylic acid 9.0 ethyl acrylate 1/0/1 8 71.3% Ethylene 9.5% acrylic acid 19.2% isobutyl acrylate Not printable cut from polyethylene terephthalate film having a highly reflective aluminum deposit on both sides thereof coated with a thin transparent coating of a copolymer comprising at least about percent ethylene and 2-15 percent acrylic acid. 

2. The coated yarn of claim 1, wherein the ethylene copolymer coating is less than 1.5 g per square meter of metallized film.
 3. The metallic yarn of claim 1 wherein the coating is a copolymer of ethylene and acrylic acid containing 2-15 percent acrylic acid.
 4. A non-laminated, non-dyeable metallic flat yarn cut from polyethylene terephthalate film having a highly reflective aluminum deposit on both sides thereof coated with a thin transparent coating of a copolymer comprising at least about 85 percent ethylene and 2-15 percent acrylic acid. 